Back cover having carbon brush holder for motor

ABSTRACT

A back cover for a motor includes a shell body, two carbon brush holders and two covering caps. The shell body has two receiving holes cut through inside and outside walls thereof. The carbon brush holders are respectively mounted in the shell body for holding a respective carbon brush bar in the receiving holes. The two carbon brush holders each have a mounting plate located in one of the receiving holes, and a spring supported on the mounting plate for forcing the carbon brush bar toward an inside of the shell body. The covering caps are respectively mounted on the outside wall of the shell body to cover the receiving holes respectively.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to motors and more particularly, toa back cover having carbon brush holders for a motor.

[0003] 2. Description of the Related Art

[0004] A conventional carbon brush holder, for example, Taiwan PatentPublication No. 273358, is comprised of a plastic holder base, a copperseat, and a covering cap. When in use, two carbon brush holders arefixedly mounted in the housing of the motor and located at two oppositesides of the comniutator to hold a respective carbon brush bar in closecontact with the commutator, achieving the expected effect. The twocarbon brush holders must be separately affixed in the housing of themotor. After installation of the carbon brush holders, a back cover ismounted on the rear side of the housing of the motor and covered overthe carbon brush holders inside the housing. When wishing to replace thecarbon brush bars after a long use of the motor, it is necessary todetach the back cover at first, and then to dismount the carbon brushholders. This carbon brush holder mounting design is complicated, inconsequence, the maintenance work is complicated.

SUMMARY OF THE INVENTION

[0005] It is the primary objective of the present invention to provide aback cover for a motor, wbich has carbon brush holders for installationof the carbon brush bars.

[0006] It is another object of the present invention to provide a backcover having carbon brush holders for a motor, which has a simplestructure and is easy to install the carbon brush bars therein.

[0007] To achieve these objectives of the present invention, the backcover for a motor provided by the present invention comprises a shellbody, two carbon brush holders and two covering caps. The shell bodyincludes two receiving holes cut through inside and outside wallsthereof. The carbon brush holders are respectively mounted in the shellbody for holding a respective carbon brush bar in the receiving holes.The two carbon brush holders each have a mounting plate located in oneof the receiving holes, and a spring supported on the mounting plate forforcing the carbon brush bar toward an inside of the shell body. Thecovering caps are respectively mounted on the outside wall of the shellbody to cover the receiving holes respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is an exploded view of a preferred embodiment of thepresent invention.

[0009]FIG. 2 is a sectional assembly view of the preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0010] Referring to FIGS. 1 and 2, a back cove 100 for mounting on arear side of a housing of a motor (not shown) is shown comprised of ashell body 10, two carbon brush holders 20, and two covering caps 30.

[0011] The shell body 10 is made of plastics, bakelite, or any suitableelectrically insulated material, comprising an annular coupling portion11, a plurality of radial supporting portions 12 inwardly backwardlyextended from the inside wall of the annular coupling portion 11 andconnected to one another, two receiving holes 13 transversely extendedthrough the inside wall and outside wall of the annular coupling portion11 and symmetrically disposed at two sides, two symmetrical pairs oflocating grooves 132 respectively formed on the outside wall of theannular coupling portion 11 corresponding to top and bottom sides of thereceiving holes 13, and two positioning grooving portions 131respectively provided in the receiving holes 13.

[0012] The carbon brush holders 20 each comprise a mounting plate 21 anda spiral spring 22. The mounting plate 21 is a metal strip comprising ahook portion 211 curved downwards from the front end thereof, an upright212 perpendicularly upwardly extended from the rear end thereof, and alocating hole 213 disposed near the front end. The spiral spring 22 is aspirally arranged spring plate rested on the mounting plate 21 andstopped at the upright 212, having a front hook 221 inserted into thelocating hole 213 of the mounting plate 21. The spiral spring 22 and themounting plate 21 are inserted into one receiving hole 13 of the shellbody 10, and then the hook portion 211 of the mounting plate 21 ishooked on the inside wall of the annular coupling portion 11, keepingthe mounting plate 21 set in the positioning grooving portion 131 of therespective receiving hole 13.

[0013] The two covering caps 30 are made of electrically insulatedmaterial, for example, plastics, each comprising two coupling flanges 31corresponding to the locating grooves 132 of the shell body 10. By meansof forcing the coupling flanges 31 into engagement with the locatinggrooves 132, the covering caps 30 are secured to the shell body 10 toclose the receiving holes 13. After mounting of the carbon brush holders20 in the receiving holes 13 of the shell body 10, the covering caps 30are respectively fastened to the locating grooves 132 of the shell body10 with the coupling flanges 31 to close the receiving holes 13.

[0014] When in use, two carbon brush bars 40 are respectively insertedinto the receiving holes 13 from the inside of the shell body 10 towardthe outside and stopped against the spiral spring 22, and then the backcove 100 is fastened to the motor's housing (not shown), keeping thecarbon brush bars 40 pressed on the commutator 50 by the spring force ofthe respective spiral springs 22. This installation procedure is quitesimple. Further, when wishing to replace the carbon brush bars 40 aftera long use, the shell body 10 is removed from the commutator 50, andthen the carbon brush bars 40 are directly removed from the receivingholes 13 for a replacement. This maintenance work is also simple.

[0015] Further, in the aforesaid embodiment, two lead wires arerespectively inserted through a respective wire hole in the peripheralwall of each receiving hole and respectively connected to the upright ofthe mounting plate of each carbon brush holder.

What is claimed is:
 1. A back cover for a motor, said back covercomprising: a shell body having an inside wall, an outside wall, and tworeceiving holes extended through said inside and outside walls; twocarbon brush holders for holding a respective carbon brush bar in saidreceiving holes, said two carbon brush holders each having a mountingplate mounted in said shell body and located in one of said receivingholes, and a spring supported on said mounting plate for forcing thecarbon brush bar toward an inside of said shell body; and two coveringcaps respectively mounted on the outside wall of said shell body tocover said receiving holes respectively.
 2. The back cover for a motoras claimed in claim 1, wherein said shell body is electricallyinsulated.
 3. The back cover for a motor as claimed in claim 1, whereinsaid shell body comprises an annular coupling portion, and a pluralityof radial supporting portions inwardly backwardly extended from aninside wall of said annular coupling portion and connected to oneanother.
 4. The back cover for a motor as claimed in claim 3, whereinsaid receiving holes are formed in said annular coupling portion at twoopposite sides.
 5. The back cover for a motor as claimed in claim 1,wherein said shell body further comprises two symmetrical pairs oflocating grooves respectively located at the outside wall correspondingto said receiving holes; said covering caps each comprise two couplingflanges respectively engaged into said locating grooves of said shellbody.
 6. The back cover for a motor as claimed in claim 1, wherein thereceiving hole has a locating grooving portion in which the mountingplate of said carbon brush holder is positioned.
 7. The back cover for amotor as claimed in claim 1, wherein the mounting plate of each saidcarbon brush holder comprises a hook portion hooked on the inside wallof said shell body.
 8. The back cover for a motor as claimed in claim 1,wherein the mounting plate of each said carbon brush holder comprises alocating hole; the spring of each said carbon brush holder is a spiralspring having a front hook inserted into the locating hole of themounting plate of the respective carbon brush holder.
 9. The back coverfor a motor as claimed in claim 1, wherein said covering caps areelectrically insulated.
 10. The back cover for a motor as claimed inclaim 1, wherein the mounting plate and the spring of each said carbonbrush holder are respectively made of metal material.